Amphoteric ion exchange resin as well as preparation method and application thereof

Abstract

The invention provides amphoteric ion exchange resin and a preparation method and application thereof, and relates to the technical field of resin separation and purification, the preparation method comprises the following steps: (1) uniformly mixing styrene, divinyl benzene, N-vinyl pyrrolidone, a primary amine group-containing monomer, a quaternary amine group-containing monomer, an initiator and a pore-foaming agent to obtain an oil phase; (2) uniformly mixing the oil phase with an aqueous solution of a dispersing agent, and initiating polymerization reaction to obtain initial resin microspheres; (3) dispersing the initial resin microspheres in an organic solvent, and adding a polysuccinimide solution for reaction to obtain grafted resin microspheres; and (4) dispersing the grafted resin microspheres in an organic solvent, and adding beta-alanine, triethylamine and water for hydrolysis reaction to obtain the amphoteric ion exchange resin. The zwitter-ion exchange group loading capacity of the prepared zwitter-ion exchange resin can be controlled and adjusted, and the zwitter-ion exchange resin has excellent hydrophilicity and biocompatibility and meets the requirements of more application scenes of the zwitter-ion exchange resin.

Description

Technical Field

[0001] This invention relates to the field of separation and purification resin technology, and in particular to a zwitterionic exchange resin, its preparation method and application. Background Technology

[0002] Amphoteric ion exchange resins are a special type of functional polymer material that contains both cation exchange groups (such as sulfonic acid groups -SO3H) and anion exchange groups (such as quaternary ammonium groups -N). + (CH3)3), thus giving it special properties and applications that ordinary single-function ion exchange resins do not have. The basic structure of zwitterionic ion exchange resins is usually composed of a three-dimensional network structure of polymer skeleton, with cation and anion functional groups connected to the skeleton by chemical bonds. Compared with traditional single ion exchange resins, the core advantages of zwitterionic resins are: (1) They can simultaneously adsorb both anions and cations; (2) They have regeneration buffering capacity: After adsorbing ions, by changing the pH value of the solution (such as switching from acidic to alkaline, or vice versa), the ions adsorbed by the resin will neutralize each other and be released in the form of salt, and the resin itself can be regenerated or partially regenerated without consuming a large amount of acid or alkali regenerator, which greatly simplifies the operation process and reduces operating costs; (3) Buffering effect: It can effectively stabilize the pH value of the solution and resist the influence of external acids and alkalis. In view of the above characteristics, zwitterionic ion exchange resins are particularly suitable for removing low concentrations of anions and cations, and are widely used in the preparation of ultrapure water, desalination and purification of pharmaceutical intermediates or products, separation and purification of proteins, and wastewater treatment and resource recovery.

[0003] Chinese patent CN202510184501.8 discloses a zwitterionic exchange resin, its preparation method, and its application. The resin is obtained by introducing the monomers 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and methacryloyloxyethyltrimethylammonium chloride into a chloromethylated polystyrene resin via atom transfer radical polymerization. This method requires prior chloromethylation of the polystyrene resin, and the content of zwitterionic exchange groups is significantly affected by the chlorine content of the polystyrene resin. The polymer chains after polymerization are prone to uneven distribution on the resin surface, and the polymerization reaction easily leads to resin pore blockage, reduced specific surface area, and decreased separation efficiency.

[0004] Chinese patent CN202411010512.6 discloses an acid-sugar separation resin and its preparation method. It utilizes sodium styrene sulfonate to modify a chloride-type strongly basic anion exchange resin through ion exchange, linking styrene sulfonate groups to the anion exchange resin. Polymerization is then initiated using a water-soluble azo compound initiator, thereby modifying the anion exchange resin with sulfonate groups to form an amphoteric ion exchange resin. However, the sulfonate group content of this resin is affected by the exchange capacity of the original strongly basic anion exchange resin. The polymerization reaction leads to a reduction in the resin's specific surface area, and some sulfonate groups may not be completely exposed after polymerization, resulting in low utilization of the sulfonate groups.

[0005] However, the existing preparation methods are cumbersome, the content of sulfonic acid cation exchange groups is uncontrollable, the surface distribution is uneven, and the resin specific surface area decreases due to the polymerization modification reaction, thereby reducing the separation efficiency. Therefore, there is an urgent need to provide a zwitterionic exchange resin, its preparation method, and its applications. Summary of the Invention

[0006] This invention provides an amphoteric ion exchange resin, its preparation method, and its application. It achieves controllable adjustment of the loading of anion and cation exchange groups, and improves the hydrophilicity and biocompatibility of the amphoteric ion exchange resin, meeting the needs of more application scenarios for amphoteric ion exchange resins.

[0007] In a first aspect, the present invention provides a method for preparing a zwitterionic ion exchange resin, the method comprising the following steps:

[0008] (1) Styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, monomers containing quaternary amine groups, initiator and porogen are mixed to obtain an oil phase;

[0009] (2) After mixing the oil phase with the aqueous solution of the dispersant, a polymerization reaction is initiated to obtain the initial resin microspheres;

[0010] (3) The initial resin microspheres are dispersed in an organic solvent and a polysuccinimide solution is added to react and obtain grafted resin microspheres;

[0011] (4) The grafted resin microspheres are dispersed in an organic solvent, and β-alanine, triethylamine and water are added to carry out a hydrolysis reaction to obtain a zwitterionic exchange resin.

[0012] Preferably, in step (1): the sum of the amounts of styrene and divinylbenzene is 20 wt% to 70 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups.

[0013] Preferably, in step (1): the amount of N-vinylpyrrolidone used is 20wt% to 30wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups.

[0014] More preferably, in step (1): the amount of the monomer containing a primary amine group or the monomer containing a quaternary amine group is 5 wt% to 30 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, the monomer containing a primary amine group and the monomer containing a quaternary amine group.

[0015] More preferably, the ratio of styrene to divinylbenzene is 1:1.

[0016] Preferably, in step (1): the monomer containing a primary amine group is a monomer containing a primary amine group and a carbon-carbon double bond.

[0017] More preferably, the monomer containing the primary amine group is at least one of allylamine, 2-aminoethyl methacrylate, and aminoethyl ethyl acrylate.

[0018] Preferably, in step (1): the monomer containing the quaternary ammonium group is a monomer containing the quaternary ammonium group and a carbon-carbon double bond.

[0019] More preferably, the quaternary ammonium group-containing monomer is at least one of methacryloyloxyethyltrimethylammonium chloride, dimethyldiallylammonium chloride, acryloyloxyethyltrimethylammonium chloride, 2-(methacryloyloxy)ethyl-2-(trimethylamino)ethyl phosphate, N-(2-acryloyloxyethyl)-N-benzyl-N,N-dimethylammonium chloride, (3-acrylamidopropyl)trimethylammonium chloride, N,N,N-trimethyl-3-(2-methylallylamino)-1-propaneammonium chloride, 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate, 3-[[2-(acryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate, and 3-[bis[2-(methacryloyloxy)ethyl](methyl)ammonium]-1-propanesulfonate.

[0020] Preferably, in step (1): the initiator is an azo initiator or a peroxide initiator; the azo initiator is preferably azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleratenitrile or benzoyl peroxide; the peroxide initiator is cyclohexanone peroxide or benzoyl peroxide.

[0021] Preferably, in step (1): the amount of the initiator is 0.5 wt% to 5 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups.

[0022] Preferably, in step (1): the pore-forming agent is at least one of toluene, xylene, cyclohexane, cyclohexanol, isooctane, n-heptane, dibutyl phthalate, n-butanol, isobutanol, n-pentanol, isopentanol, n-butyl ether, isobutyl ether, n-pentanol, and isopentanol.

[0023] More preferably, the amount of the pore-forming agent is 1 wt% to 80 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups.

[0024] Preferably, in step (2): the dispersant is one of polyvinylpyrrolidone, polyvinyl alcohol, polyethyleneimine, carboxymethyl cellulose, gelatin and gum arabic.

[0025] More preferably, the mass fraction of the dispersant in the aqueous solution is 0.1 wt% to 10 wt%.

[0026] Preferably, in step (2), the ratio of the amount of the oil phase to the aqueous solution of the dispersant is (0.1 to 1):1.

[0027] Preferably, in step (2): the temperature of the polymerization reaction is 65-90°C and the reaction time is 12-24h.

[0028] More preferably, after the polymerization reaction is completed, the initial resin microspheres are obtained by sequentially filtering, washing, and drying.

[0029] Preferably, in step (3): the mass ratio of polysuccinimide in the polysuccinimide solution to the initial resin microspheres is (0.1 to 1):1.

[0030] Preferably, in step (3), the ratio of polysuccinimide to organic solvent in the polysuccinimide solution is 1:(1-10).

[0031] More preferably, in step (3): the temperature of the reaction is 25-30°C and the time is 20-36h.

[0032] More preferably, the polysuccinimide is prepared by the following method: aspartic acid is polymerized at 160-250°C to obtain an initial product, which is then dissolved in N,N-dimethylformamide by heating, and the supernatant is collected by centrifugation. The supernatant is then recrystallized and dried sequentially to obtain polysuccinimide.

[0033] Preferably, in step (4), the mass ratio of β-alanine, triethylamine, water and grafted resin microspheres is (0.1-1):(0.1-1):(1-10):1.

[0034] In a second aspect, the present invention provides a zwitterionic exchange resin, which is prepared by any of the preparation methods described in the first aspect above.

[0035] Thirdly, the present invention provides an application of the zwitterionic exchange resin described in the second aspect above, which is used in the fields of water treatment, protein purification, and preparation of ultra-high purity electronic-grade hydrogen peroxide.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] This invention utilizes styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, and monomers containing quaternary amine groups to prepare initial resin microspheres via suspension polymerization. These microspheres are then modified with a polysuccinimide coating and hydrolyzed to form a polyaspartic acid coating, resulting in a zwitterionic exchange resin containing carboxyl, secondary amine, and quaternary amine groups. The content of carboxyl, secondary amine, and quaternary amine groups in this resin can be controlled by adjusting the monomer content and the amount of polysuccinimide used. The final polyaspartic acid coating and N-vinylpyrrolidone impart excellent biocompatibility and hydrophilicity, enabling this zwitterionic exchange resin to have wide applications in water treatment, protein purification, and the preparation of ultra-high purity electronic-grade hydrogen peroxide.

[0038] Instruction manual illustrations

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 This is a flowchart of a method for preparing a zwitterionic ion exchange resin according to an embodiment of the present invention;

[0041] Figure 2 This is an optical microscope image of the initial resin microspheres provided in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the synthesis route of the zwitterionic exchange resin provided in Embodiment 7 of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] This invention provides a method for preparing a zwitterionic ion exchange resin, such as... Figure 1 As shown, the preparation method includes the following steps:

[0045] (1) Styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, monomers containing quaternary amine groups, initiator and porogen are mixed to obtain an oil phase;

[0046] (2) After mixing the oil phase with the aqueous solution of the dispersant, a polymerization reaction is initiated to obtain the initial resin microspheres;

[0047] (3) The initial resin microspheres were dispersed in an organic solvent and polysuccinimide solution was added to react and obtain grafted resin microspheres.

[0048] (4) The grafted resin microspheres were dispersed in an organic solvent and β-alanine, triethylamine and water were added to carry out a hydrolysis reaction to obtain zwitterionic exchange resin.

[0049] In this embodiment of the invention, styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, and monomers containing quaternary amine groups are used to prepare initial resin microspheres through suspension polymerization. These microspheres are then modified with a polysuccinimide coating and hydrolyzed to form a polyaspartic acid coating, resulting in a zwitterionic exchange resin containing carboxyl, secondary amine, and quaternary amine groups. Thus, the content of carboxyl, secondary amine, and quaternary amine groups in the resin can be controlled by the monomer content and the amount of polysuccinimide used. The final polyaspartic acid coating and N-vinylpyrrolidone impart good biocompatibility and hydrophilicity, enabling this zwitterionic exchange resin to have wide applications in water treatment, protein purification, and the preparation of ultra-high purity electronic-grade hydrogen peroxide.

[0050] According to some preferred embodiments, in step (1): the sum of the amounts of styrene and divinylbenzene is 20 wt% to 70 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups.

[0051] According to some preferred embodiments, in step (1): the amount of N-vinylpyrrolidone used is 20wt% to 30wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups.

[0052] According to some preferred embodiments, in step (1): the amount of the monomer containing a primary amine group or the monomer containing a quaternary amine group is 5 wt% to 30 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, the monomer containing a primary amine group and the monomer containing a quaternary amine group.

[0053] For 20wt% to 70wt%, specifically any value between 20wt% and 70wt%, for example, it can be 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt%, or 70wt%.

[0054] For 20wt% to 30wt%, specifically any value between 20wt% and 30wt%, for example, it can be 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, or 30wt%.

[0055] For 5wt% to 30wt%, specifically any value between 5wt% and 30wt%, for example, it can be 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, or 30wt%.

[0056] According to some preferred embodiments, the ratio of styrene to divinylbenzene is 1:1.

[0057] In this embodiment of the invention, due to the hydrophobicity of polystyrene / divinylbenzene and its poor wettability with aqueous solutions, the adsorption efficiency for anions, cations, and charged proteins in aqueous solutions is greatly limited. Therefore, by introducing the functional groups of N-vinylpyrrolidone and modifying with polysuccinimide and generating amine groups through hydrolysis, the zwitterionic exchange resin is endowed with excellent hydrophilicity and biocompatibility, thereby improving its ion exchange efficiency and application range. Experiments have shown that if the amount of styrene and divinylbenzene is too small, the mechanical properties of the zwitterionic exchange resin are poor; however, if the amount of styrene and divinylbenzene is too large, it will reduce the hydrophilicity of the zwitterionic exchange resin, leading to poor wettability of the macroporous adsorption resin with aqueous solutions, thus reducing adsorption efficiency and ion exchange capacity. Therefore, the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, and monomers containing quaternary amine groups are limited to the above-mentioned ranges.

[0058] According to some preferred embodiments, in step (1): the monomer containing a primary amine group is a monomer containing a primary amine group and a carbon-carbon double bond.

[0059] According to some preferred embodiments, the monomer containing the primary amine group is at least one of allylamine, 2-aminoethyl methacrylate, and aminoethyl ethyl acrylate.

[0060] It should be noted that "at least one" means any one or more of them mixed in any proportion.

[0061] According to some preferred embodiments, in step (1): the quaternary ammonium group monomer is a monomer containing a quaternary ammonium group and a carbon-carbon double bond.

[0062] According to some more preferred embodiments, the quaternary ammonium group-containing monomer is at least one of methacryloyloxyethyltrimethylammonium chloride, dimethyldiallylammonium chloride, acryloyloxyethyltrimethylammonium chloride, 2-(methacryloyloxy)ethyl-2-(trimethylamino)ethyl phosphate, N-(2-acryloyloxyethyl)-N-benzyl-N,N-dimethylammonium chloride, (3-acrylamidopropyl)trimethylammonium chloride, N,N,N-trimethyl-3-(2-methylallylamino)-1-propaneammonium chloride, 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate, 3-[[2-(acryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate, and 3-[bis[2-(methacryloyloxy)ethyl](methyl)ammonium]-1-propanesulfonate.

[0063] According to some preferred embodiments, in step (1): the initiator is an azo initiator or a peroxide initiator; the azo initiator is preferably azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleratenitrile or benzoyl peroxide; the peroxide initiator is cyclohexanone peroxide or benzoyl peroxide.

[0064] According to some preferred embodiments, in step (1): the amount of initiator is 0.5 wt% to 5 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups (for example, it can be 0.5 wt%, 0.8 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%).

[0065] According to some preferred embodiments, in step (1): the pore-forming agent is at least one of toluene, xylene, cyclohexane, cyclohexanol, isooctane, n-heptane, dibutyl phthalate, n-butanol, isobutanol, n-pentanol, isopentanol, n-butyl ether, isobutyl ether, n-pentanol, and isopentanol.

[0066] According to some preferred embodiments, the amount of pore-forming agent is 1 wt% to 80 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups (e.g., it can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, or 80 wt%).

[0067] In this invention, initial resin microspheres with a macroporous structure are prepared by adding a porogen, and the pore size and porosity in the zwitterionic exchange resin are controlled by adjusting the amount of porogen. Thus, by controlling the amount of porogen, a porous structure is formed to suit the adsorption requirements of anions, cations, and proteins with different charges. This avoids the situation where insufficient porogen leads to small pore size, insufficient specific surface area, and limited adsorption capacity, resulting in poor adsorption performance, reduced ability to remove anions and cations, or poor protein purification. Conversely, excessive porogen leads to large pore size, causing target molecules to rapidly pass through the zwitterionic exchange resin, thereby reducing adsorption performance and ion exchange capacity. It also avoids the problems of easily broken and unstable zwitterionic exchange resins caused by excessively large pore sizes.

[0068] According to some preferred embodiments, in step (2): the dispersant is one of polyvinylpyrrolidone, polyvinyl alcohol, polyethyleneimine, carboxymethyl cellulose, gelatin and gum arabic.

[0069] According to some preferred embodiments, the mass fraction of the dispersant in the aqueous solution is 0.1 wt% to 10 wt% (e.g., it can be 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%).

[0070] According to some preferred embodiments, the ratio of the oil phase to the aqueous dispersant is (0.1 to 1):1 (for example, it can be 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1 or 1:1).

[0071] In this invention, experiments have confirmed that if the ratio of the oil phase to the aqueous dispersant solution is greater than 1:1, the amount of oil phase is excessive, the dispersant is relatively insufficient, and the monomer droplets cannot be effectively stabilized, resulting in uneven particle size distribution of the zwitterionic exchange resin, which in turn affects the adsorption capacity and ion exchange performance. If the ratio of the oil phase to the aqueous dispersant solution is less than 0.1:1, the amount of oil phase is insufficient, the monomer concentration is inadequate, and the polymerization rate decreases, resulting in zwitterionic exchange resin with excessively small particle size, excessively large pore size, and loose structure, which will further affect the adsorption capacity and ion exchange performance. Therefore, the ratio of the oil phase to the aqueous dispersant solution is limited to (0.1~1):1.

[0072] According to some preferred embodiments, in step (2): the temperature of the polymerization reaction is 65 to 90°C (for example, it can be 65°C, 70°C, 75°C, 80°C, 85°C or 90°C), and the reaction time is 12 to 24 hours (for example, it can be 12 hours, 14 hours, 15 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours).

[0073] According to some preferred embodiments, after the polymerization reaction is completed, the initial microspheres are obtained by sequentially filtration, washing, and drying.

[0074] Specifically, after the polymerization reaction is completed, the obtained product is sequentially filtered, washed with water, and washed with ethanol to remove the pore-forming agent and unreacted raw materials. Then, it is dried and sieved to obtain the initial resin microspheres of the desired particle size.

[0075] In this embodiment of the invention, five monomers—styrene, divinylbenzene, N-vinylpyrrolidone, a monomer containing a primary amine group, and a monomer containing a quaternary amine group—were introduced into a suspension polymerization reaction to prepare oil-in-water initial resin microspheres with both excellent mechanical strength and hydrophilicity. N-vinylpyrrolidone provides a weakly basic group, the monomer containing the primary amine group provides a weakly basic group, and the monomer containing the quaternary amine group provides a strong basic group; all three possess anion exchange functionality, thus providing anion exchange groups for the zwitterionic exchange resin. Meanwhile, experiments have shown that if the amount of the monomer containing the primary amine group is less than 5 wt%, the cation exchange performance of the zwitterionic exchange resin will be affected; if the amount of the monomer containing the quaternary amine group is less than 5 wt%, the strong basic anion exchange performance of the prepared zwitterionic exchange resin will be poor.

[0076] According to some preferred embodiments, in step (3): the mass ratio of polysuccinimide in the polysuccinimide solution to the initial resin microspheres is (0.1 to 1):1 (for example, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1 or 1:1).

[0077] It should be noted that the organic solvent in step (3) is any organic solvent that can disperse the initial resin microspheres and polysuccinimide.

[0078] In this embodiment of the invention, experiments have confirmed that if the mass ratio of polysuccinimide to initial resin microspheres is greater than 1:1, the excessive amount of polysuccinimide will reduce the specific surface area of ​​the resin microspheres and may even cause pore blockage. However, if the mass ratio of polysuccinimide to initial resin microspheres is less than 0.1:1, the insufficient amount of polysuccinimide results in less grafting of polysuccinimide onto the initial resin microspheres, i.e., lower modification density and fewer cation exchange sites provided, which will reduce the cation exchange function of the final zwitterionic exchange resin. Thus, since the initial resin microspheres have anion exchange groups, by controlling the amount of polysuccinimide to initial resin microspheres, the final zwitterionic exchange resin can possess both anion exchange groups and cation exchange groups.

[0079] According to some preferred embodiments, in step (3), the ratio of polysuccinimide to organic solvent in the polysuccinimide solution is 1:(1 to 10) (for example, it can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5 or 1:10).

[0080] In this embodiment of the invention, experiments have confirmed that if the ratio of polysuccinimide to organic solvent in the polysuccinimide solution is less than 1:10, the concentration of the polysuccinimide solution is too low, the collision probability between the primary amine groups and the polysuccinimide decreases, the effective grafting points decrease, and it may even only modify the surface layer of the initial resin microspheres, thereby reducing the cation exchange function of the zwitterionic exchange resin. If the ratio of polysuccinimide to organic solvent in the polysuccinimide solution is greater than 1:1, the concentration of the polysuccinimide solution is too high, which may lead to over-grafting or pore blockage, and may even cause side reactions due to insufficient organic solvent, thereby reducing the ion exchange performance of the zwitterionic exchange resin.

[0081] According to some more preferred embodiments, in step (3): the reaction temperature is 25-30°C (e.g., 25°C, 26°C, 27°C, 28°C, 29°C or 30°C), and the time is 20-36h (e.g., 20h, 25h, 30h, 35h or 36h).

[0082] According to some preferred embodiments, polysuccinimide is prepared by the following method: aspartic acid is polymerized at 160-250°C (e.g., 160°C, 165°C, 170°C, 175°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C) to obtain an initial product, which is then dissolved in N,N-dimethylformamide by heating, and the supernatant is collected by centrifugation. The supernatant is then recrystallized and dried sequentially to obtain polysuccinimide.

[0083] Specifically, aspartic acid is polymerized in an oven at 160–250°C to obtain a light brown solid, which is then dissolved by heating with N,N-dimethylformamide. The supernatant is collected by centrifugation. The supernatant is recrystallized with diethyl ether to obtain a light leather-colored precipitate, which is dried to obtain polysuccinimide.

[0084] According to some preferred embodiments, in step (4), the mass ratio of β-alanine, triethylamine, water and grafted resin microspheres is (0.1-1):(0.1-1):(1-10):1.

[0085] It should be noted that the mass ratio of β-alanine to grafted resin microspheres is (0.1-1):1, for example, it can be 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, or 1:1; the mass ratio of triethylamine to grafted resin microspheres is (0.1-1):1, for example, it can be 0.1:1, 0.15:1, 0.2:1, or 0.25:1. The ratios of water to grafted resin microspheres can be 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, or 1:1; the mass ratio of water to grafted resin microspheres is (1-10):1, for example, it can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1.

[0086] According to some more preferred embodiments, in step (4): the temperature of the hydrolysis reaction is 25 to 30°C (for example, it can be 25°C, 26°C, 27°C, 28°C, 29°C or 30°C), and the time is 20 to 36 hours (for example, it can be 20 hours, 25 hours, 30 hours, 35 hours or 36 hours).

[0087] It should be noted that the organic solvent in step (4) is any organic solvent that can disperse the grafted resin microspheres.

[0088] In this embodiment of the invention, the loading of cation exchange groups is controlled by the amount of polyaspartic acid obtained from the final hydrolysis reaction, while the loading of anion exchange groups is mainly achieved through primary amine groups, quaternary amine groups, N-vinylpyrrolidone, and polysuccinimide. Thus, by controlling the amount of each monomer and polysuccinimide used in each step, the loading of ion exchange groups in the zwitterionic exchange resin can be controlled. It should be noted that the amino groups in polyaspartic acid also have weakly basic groups; therefore, the zwitterionic exchange resin is achieved through the synergistic control of polyaspartic acid, primary amine groups, quaternary amine groups, and N-vinylpyrrolidone.

[0089] The present invention also provides a zwitterionic ion exchange resin, which is prepared by the preparation method provided in the present invention.

[0090] This invention also provides an application of the zwitterionic exchange resin prepared by any of the above methods, which can be used in water treatment, protein purification and preparation of ultra-high purity electronic-grade hydrogen peroxide.

[0091] To more clearly illustrate the technical solution and advantages of the present invention, the following detailed description of an amphoteric ion exchange resin, its preparation method, and its application is provided through several embodiments.

[0092] In the following examples, polysuccinimide was prepared using the following method:

[0093] 10g of aspartic acid was weighed and polymerized in an oven at 190℃ for 48 hours to obtain a light brown solid. This solid was then dissolved by heating with N,N-dimethylformamide (DMF). The supernatant was collected by centrifugation, and the small amount of white precipitate in the lower layer was discarded. The supernatant was recrystallized from diethyl ether to obtain a light leather-colored precipitate. This precipitate was washed several times with diethyl ether to replace the DMF, and then dried to obtain the polysuccinimide polymer.

[0094] Example 1

[0095] (1) Dissolve 5g styrene, 5g divinylbenzene, 10g N-vinylpyrrolidone, 15g allylamine and 15g methacryloyloxyethyltrimethylammonium chloride in a pore-forming agent (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0096] (2) Preparation of the aqueous solution of the dispersant: Dissolve 1g of polyvinyl alcohol in 60g of water by heating, and cool for later use; add the oil phase from step (1) to the aqueous solution of the dispersant (i.e., the aqueous phase), mix mechanically at 400rpm, and heat to 70℃ for polymerization reaction for 24h; after the reaction, filter, wash with water, wash with ethanol, and dry the product to obtain the initial resin microspheres, such as Figure 2 As shown.

[0097] Example 2

[0098] (1) Dissolve 5g styrene, 5g divinylbenzene, 15g N-vinylpyrrolidone, 12.5g allylamine and 12.5g methacryloyloxyethyltrimethylammonium chloride in a pore-forming agent (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0099] (2) Preparation of the aqueous solution of the dispersant: 1g of polyvinyl alcohol is heated and dissolved in 60g of water and cooled for later use; the oil phase of step (1) is added to the aqueous solution of the dispersant (i.e., the aqueous phase), and mechanically stirred at 400rpm to mix evenly, and the temperature is raised to 70℃ for polymerization reaction for 24h; after the reaction is completed, the product is filtered, washed with water, washed with ethanol, and dried to obtain the initial resin microspheres.

[0100] Example 3

[0101] (1) Dissolve 17.5g styrene, 17.5g divinylbenzene, 10g N-vinylpyrrolidone, 2.5g allylamine and 2.5g methacryloyloxyethyltrimethylammonium chloride in a porogen (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0102] (2) Preparation of the aqueous solution of the dispersant: 1g of polyvinyl alcohol is heated and dissolved in 60g of water and cooled for later use; the oil phase of step (1) is added to the aqueous solution of the dispersant (i.e., the aqueous phase), and mechanically stirred at 400rpm to mix evenly, and the temperature is raised to 70℃ for polymerization reaction for 24h; after the reaction is completed, the product is filtered, washed with water, washed with ethanol, and dried to obtain the initial resin microspheres.

[0103] Example 4

[0104] (1) Dissolve 5g styrene, 5g divinylbenzene, 10g N-vinylpyrrolidone, 15g ethyl aminoethyl acrylate and 15g methacryloyloxyethyltrimethylammonium chloride in a pore-forming agent (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0105] (2) Preparation of the aqueous solution of the dispersant: 1g of polyvinyl alcohol is heated and dissolved in 60g of water and cooled for later use; the oil phase of step (1) is added to the aqueous solution of the dispersant (i.e., the aqueous phase), and mechanically stirred at 400rpm to mix evenly, and the temperature is raised to 70℃ for polymerization reaction for 24h; after the reaction is completed, the product is filtered, washed with water, washed with ethanol, and dried to obtain the initial resin microspheres.

[0106] Example 5

[0107] (1) Dissolve 5g styrene, 5g divinylbenzene, 10g N-vinylpyrrolidone, 15g allylamine and 15g acryloyloxyethyltrimethylammonium chloride in a pore-forming agent (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0108] (2) Preparation of the aqueous solution of the dispersant: 1g of polyvinyl alcohol is heated and dissolved in 60g of water and cooled for later use; the oil phase of step (1) is added to the aqueous solution of the dispersant (i.e., the aqueous phase), and mechanically stirred at 400rpm to mix evenly, and the temperature is raised to 70℃ for polymerization reaction for 24h; after the reaction is completed, the product is filtered, washed with water, washed with ethanol, and dried to obtain the initial resin microspheres.

[0109] Example 6

[0110] Example 6 is basically the same as Example 1, except that the monomer containing the quaternary ammonium group is 3-[[2-(acryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate.

[0111] Example 7

[0112] S1: The initial resin microspheres of Example 1 were modified with polysuccinimide: 10g of initial resin microspheres were ultrasonically dispersed in 200mL of DMF, and 1g of polysuccinimide polymer was dissolved in 50mL of DMF to obtain a polysuccinimide solution; the polysuccinimide solution was added to the dispersion of the initial resin microspheres and reacted at room temperature (25℃) for 24h. After the reaction was completed, the mixture was filtered, washed and dried in sequence to obtain polysuccinimide-modified resin microspheres, i.e., grafted resin microspheres.

[0113] S2: Polyaspartic acid-modified resin microspheres (i.e., zwitterionic exchange resin): 10g of grafted resin microspheres were ultrasonically dispersed in 100mL DMF, and 10mL of water, 1mL of triethylamine, and 1mL of β-alanine were added. The reaction was carried out at room temperature (25℃) for 24h. After the reaction was completed, the mixture was washed successively with DMF, dilute hydrochloric acid, and water to obtain a zwitterionic exchange resin containing carboxyl, secondary amine, and quaternary amine groups. Figure 3 As shown.

[0114] Example 8

[0115] S1: The initial resin microspheres from Example 1 were modified with polysuccinimide: 10g of initial resin microspheres were ultrasonically dispersed in 200mL of DMF, and 2g of polysuccinimide polymer was dissolved in 50mL of DMF to obtain a polysuccinimide solution; the polysuccinimide solution was added to the dispersion of the initial resin microspheres and reacted at room temperature (25℃) for 24h. After the reaction was completed, the microspheres were filtered, washed, and dried to obtain polysuccinimide-modified resin microspheres, i.e., grafted resin microspheres.

[0116] S2: Polyaspartic acid modified resin microspheres (i.e. zwitterionic exchange resin): 10g of grafted resin microspheres were ultrasonically dispersed in 100mL of DMF, and 10mL of water, 1mL of triethylamine and 1mL of β-alanine were added. The reaction was carried out at room temperature (25℃) for 24h. After the reaction was completed, the zwitterionic exchange resin containing carboxyl, secondary amine and quaternary amine groups was obtained by washing with DMF, dilute hydrochloric acid and water in sequence.

[0117] Example 9

[0118] S1: The initial resin microspheres of Example 1 were modified with polysuccinimide: 10g of initial resin microspheres were ultrasonically dispersed in 200mL of DMF, and 10g of polysuccinimide polymer was dissolved in 50mL of DMF to obtain a polysuccinimide solution; the polysuccinimide solution was added to the dispersion of the initial resin microspheres and reacted at room temperature (25℃) for 24h. After the reaction was completed, the mixture was filtered, washed and dried in sequence to obtain polysuccinimide-modified resin microspheres, i.e., grafted resin microspheres.

[0119] S2: Polyaspartic acid modified resin microspheres (i.e. zwitterionic exchange resin): 10g of grafted resin microspheres were ultrasonically dispersed in 100mL of DMF, and 10mL of water, 1mL of triethylamine and 1mL of β-alanine were added. The reaction was carried out at room temperature (25℃) for 24h. After the reaction was completed, the zwitterionic exchange resin containing carboxyl, secondary amine and quaternary amine groups was obtained by washing with DMF, dilute hydrochloric acid and water in sequence.

[0120] Example 10

[0121] Example 10 is basically the same as Example 7, except that it uses the initial resin microspheres from Example 2.

[0122] Example 11

[0123] Example 11 is basically the same as Example 9, except that it uses the initial resin microspheres from Example 2.

[0124] Example 12

[0125] Example 12 is basically the same as Example 7, except that it uses the initial resin microspheres from Example 3.

[0126] Example 13

[0127] Example 13 is basically the same as Example 9, except that it uses the initial resin microspheres from Example 3.

[0128] Example 14

[0129] Example 14 is basically the same as Example 7, except that it uses the initial resin microspheres from Example 5.

[0130] Example 15

[0131] Example 15 is basically the same as Example 9, except that it uses the initial resin microspheres from Example 5.

[0132] Example 16

[0133] Example 16 is basically the same as Example 7, except that it uses the initial resin microspheres from Example 6.

[0134] Example 17

[0135] Example 17 is basically the same as Example 9, except that it uses the initial resin microspheres from Example 6.

[0136] Comparative Example 1

[0137] The grafted resin microspheres from Example 7 were used as the product, in which the polysuccinimide in the grafted resin microspheres was not hydrolyzed.

[0138] Comparative Example 2

[0139] Comparative Example 2 is basically the same as Example 7, except that allylamine was not added during the preparation of the initial resin microspheres;

[0140] Specifically, the preparation process of the initial resin microspheres includes:

[0141] (1) Dissolve 5g styrene, 5g divinylbenzene, 10g N-vinylpyrrolidone and 30g methacryloyloxyethyltrimethylammonium chloride in a porogen (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0142] (2) Preparation of the aqueous solution of the dispersant: 1g of polyvinyl alcohol is heated and dissolved in 60g of water and cooled for later use; the oil phase of step (1) is added to the aqueous solution of the dispersant (i.e., the aqueous phase), and mechanically stirred at 400rpm to mix evenly, and the temperature is raised to 70℃ for polymerization reaction for 24h; after the reaction is completed, the product is filtered, washed with water, washed with ethanol, and dried to obtain the initial resin microspheres.

[0143] Comparative Example 3

[0144] Comparative Example 3 is basically the same as Example 7, except that: no methacryloyloxyethyltrimethylammonium chloride was added during the preparation of the initial resin microspheres;

[0145] Specifically, the preparation process of the initial resin microspheres includes:

[0146] (1) Dissolve 5g styrene, 5g divinylbenzene, 10g N-vinylpyrrolidone and 30g allylamine in a porogen (composed of 25g toluene and 7.5g dibutyl phthalate) to obtain a monomer mixed solution. Then add 0.5g benzoyl peroxide to the monomer mixed solution to dissolve and mix well to obtain the oil phase.

[0147] (2) Preparation of the aqueous solution of the dispersant: 1g of polyvinyl alcohol is heated and dissolved in 60g of water and cooled for later use; the oil phase of step (1) is added to the aqueous solution of the dispersant (i.e., the aqueous phase), and mechanically stirred at 400rpm to mix evenly, and the temperature is raised to 70℃ for polymerization reaction for 24h; after the reaction is completed, the product is filtered, washed with water, washed with ethanol, and dried to obtain the initial resin microspheres.

[0148] Comparative Example 4

[0149] Comparative Example 4 is basically the same as Example 7, except that 0.5g of polysuccinimide polymer is dissolved in 50mL of DMF to obtain a polysuccinimide solution.

[0150] Comparative Example 5

[0151] Comparative Example 5 is basically the same as Example 7, except that 11g of polysuccinimide polymer was dissolved in 50mL of DMF to obtain a polysuccinimide solution.

[0152] The amphoteric ion exchange resins and products obtained in the examples and comparative examples were subjected to ion exchange capacity tests, and the test results are shown in Table 1. The ion exchange capacity test methods were in accordance with national standards GB / T 5760-2000, GB / T8144-2008, GB / T 11992-2008, and GB / T 19861-2005.

[0153] Table 1

[0154]

[0155]

[0156] Figure 2 An optical microscope image of the initial resin microspheres provided in Example 1 is shown, showing that the initial resin microspheres have a uniform particle size distribution. Figure 3 A synthetic route for preparing zwitterionic exchange resins from initial resin microspheres is shown.

[0157] As shown in Table 1, the zwitterionic exchange resin prepared using this invention possesses both anion exchange groups and cation exchange groups, solving the problems of uncontrollable ion exchange group loading and poor biocompatibility in zwitterionic exchange resins. This meets the needs of more application scenarios for zwitterionic exchange resins, thus finding wide application in water treatment, protein purification, and the preparation of ultra-high purity electronic-grade hydrogen peroxide. Comparative Example 1 uses unhydrolyzed grafted resin microspheres containing polysuccinimide. Since polysuccinimide lacks carboxyl groups, it has no weak acid exchange capacity compared to Example 7. Comparative Example 2, compared to Example 7, does not contain monomers with primary amine groups, so it cannot react with polysuccinimide. However, it contains an excess of monomers with quaternary amine groups, thus significantly increasing the strong base group exchange capacity and significantly decreasing the weak base group exchange capacity, with no weak acid cation exchange capacity. Comparative Example 3, compared to Example 7, does not contain monomers with quaternary amine groups, but it contains an excess of monomers with primary amine groups. Therefore, the strong base group exchange capacity is zero, while the weak base group exchange capacity is significantly increased. Compared to Example 7, Comparative Example 4 showed a decrease in weak acid group exchange capacity and fewer cation exchange sites due to insufficient polysuccinimide polymer. Compared to Example 7, Comparative Example 5 showed a decrease in base group exchange capacity and fewer anion exchange sites due to excessive polysuccinimide polymer, which caused partial pore blockage.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. The parts of the present invention not described in detail are techniques known to those skilled in the art.

Claims

1. A method for preparing a zwitterionic ion exchange resin, characterized in that, include: (1) Styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, monomers containing quaternary amine groups, initiator and porogen are mixed to obtain an oil phase; (2) After mixing the oil phase with the aqueous solution of the dispersant, a polymerization reaction is initiated to obtain the initial resin microspheres; (3) The initial resin microspheres are dispersed in an organic solvent and a polysuccinimide solution is added to react and obtain grafted resin microspheres; (4) The grafted resin microspheres are dispersed in an organic solvent, and β-alanine, triethylamine and water are added to carry out a hydrolysis reaction to obtain a zwitterionic exchange resin.

2. The preparation method according to claim 1, characterized in that, In step (1): The sum of the amounts of styrene and divinylbenzene is 20 wt% to 70 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, and monomers containing quaternary amine groups; and / or, The amount of N-vinylpyrrolidone used is 20 wt% to 30 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups and monomers containing quaternary amine groups; Preferably, the amount of the monomer containing a primary amine group or the monomer containing a quaternary amine group is 5 wt% to 30 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, the monomer containing a primary amine group, and the monomer containing a quaternary amine group. More preferably, the ratio of styrene to divinylbenzene is 1:

1.

3. The preparation method according to claim 1, characterized in that, In step (1): The monomer containing the primary amine group is a monomer containing a primary amine group and a carbon-carbon double bond, preferably at least one of allylamine, 2-aminoethyl methacrylate, and aminoethyl acrylate; and / or, The quaternary ammonium group-containing monomer is a monomer containing a quaternary ammonium group and a carbon-carbon double bond, preferably at least one of the following: methacryloyloxyethyltrimethylammonium chloride, dimethyl diallyl ammonium chloride, acryloyloxyethyltrimethylammonium chloride, 2-(methacryloyloxy)ethyl-2-(trimethylamino)ethyl phosphate, N-(2-acryloyloxyethyl)-N-benzyl-N,N-dimethylammonium chloride, (3-acrylamidopropyl)trimethylammonium chloride, N,N,N-trimethyl-3-(2-methylallylamino)-1-propaneammonium chloride, 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate, 3-[[2-(acryloyloxy)ethyl]dimethylammonium]propane-1-sulfonate, and 3-[bis[2-(methacryloyloxy)ethyl](methyl)ammonium]-1-propanesulfonate.

4. The preparation method according to claim 1, characterized in that, In step (1): The initiator is an azo initiator or a peroxide initiator; the azo initiator is preferably azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovalerate, or benzoyl peroxide; the peroxide initiator is cyclohexanone peroxide or benzoyl peroxide. Preferably, the amount of the initiator is 0.5 wt% to 5 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, and monomers containing quaternary amine groups; and / or, The pore-forming agent is at least one selected from toluene, xylene, cyclohexane, cyclohexanol, isooctane, n-heptane, dibutyl phthalate, n-butanol, isobutanol, n-pentanol, isopentanol, n-butyl ether, isobutyl ether, n-pentanol, and isopentanol. Preferably, the amount of the pore-forming agent is 1 wt% to 80 wt% of the sum of the amounts of styrene, divinylbenzene, N-vinylpyrrolidone, monomers containing primary amine groups, and monomers containing quaternary amine groups.

5. The preparation method according to claim 1, characterized in that, In step (2): The dispersant is one of polyvinylpyrrolidone, polyvinyl alcohol, polyethyleneimine, carboxymethyl cellulose, gelatin, and gum arabic; preferably, the mass fraction of the dispersant in the aqueous solution is 0.1 wt% to 10 wt%; and / or, The ratio of the amount of oil phase to the aqueous solution of the dispersant is (0.1 to 1):

1.

6. The preparation method according to claim 1, characterized in that, In step (2): The polymerization reaction is carried out at a temperature of 65–90°C for 12–24 hours. Preferably, after the polymerization reaction is completed, the initial resin microspheres are obtained by sequentially filtering, washing, and drying.

7. The preparation method according to claim 1, characterized in that, In step (3): The mass ratio of polysuccinimide to the initial resin microspheres in the polysuccinimide solution is (0.1–1):1; and / or, The ratio of polysuccinimide to organic solvent in the polysuccinimide solution is 1:(1-10); Preferably, the reaction temperature is 25–30°C and the time is 20–36 h; More preferably, the polysuccinimide is prepared by the following method: aspartic acid is polymerized at 160-250°C to obtain an initial product, which is then dissolved in N,N-dimethylformamide by heating, and the supernatant is collected by centrifugation. The supernatant is then recrystallized and dried sequentially to obtain polysuccinimide.

8. The preparation method according to any one of claims 1 to 7, characterized in that, In step (4): The mass ratio of β-alanine, triethylamine, water, and the grafted resin microspheres is (0.1-1):(0.1-1):(1-10):

1.

9. A zwitterionic exchange resin, characterized in that, It is prepared by any of the preparation methods described in claims 1 to 8.

10. An application of the zwitterionic ion exchange resin as described in claim 9, characterized in that, It is used in water treatment, protein purification, and the preparation of ultra-high purity electronic-grade hydrogen peroxide.

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